Memento Kubernetes

Introduction to Kubernetes¶

What is Kubernetes? - Kubernetes is an open-source platform for automating the deployment, scaling, and management of containerized applications. - It groups containers into logical units for easy management and discovery. - Kubernetes provides high availability, scalability, and fault tolerance for applications in production.

Prerequisites¶

Before starting, you’ll need: - A basic understanding of containers (Docker) - Access to a Kubernetes cluster (local or cloud-based) - kubectl (Kubernetes command-line tool) - A container registry (e.g., Docker Hub)

Setting Up Kubernetes Cluster¶

Using Minikube for a Local Cluster: - Minikube allows you to run Kubernetes clusters locally.

Install Minikube:

brew install minikube

Start the Minikube Cluster:

minikube start

Check Cluster Status:

kubectl cluster-info

Deploying a Simple Application on Kubernetes¶

Create a deployment YAML file: - Example: deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

Deploy the application:

kubectl apply -f deployment.yaml

Check the deployment status:

kubectl get deployments

Exposing the Application¶

Expose the deployment via a service: - Example: service.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: LoadBalancer

Create the service:

kubectl apply -f service.yaml

Get the external IP of the service:

kubectl get svc nginx-service

Scaling the Application¶

Scale the number of replicas:

kubectl scale deployment nginx-deployment --replicas=3

Verify the new number of pods:

kubectl get pods

Updating the Application¶

Update the deployment with a new image:

kubectl set image deployment/nginx-deployment nginx=nginx:latest

Check if the deployment was updated:

kubectl rollout status deployment/nginx-deployment

Deleting Resources¶

Delete the service and deployment:

kubectl delete -f service.yaml
kubectl delete -f deployment.yaml

Conclusion¶

Key Takeaways: - Kubernetes helps with managing containerized applications in production with features like scaling, monitoring, and self-healing. - The key components include Pods, Deployments, and Services. - Kubernetes provides high availability, fault tolerance, and easy scaling.

Next Steps: - Learn about ConfigMaps and Secrets for managing application configuration. - Explore Helm for easier package management in Kubernetes. - Experiment with Kubernetes in the cloud (e.g., GKE, EKS, AKS).

Last update : 2025-05-04T19:26:13Z